Prevalence of fish and shellfish allergy: a systematic review

RationaleAccurate information on prevalence of food allergy allows a more evidence-based approach to planning of allergy services. Additionally reporting on the totality of evidence relating to specific food allergy can establish geographical variation which may exist.MethodsSearches were conducted using two databases; Web of Science and PubMed. Initially 985 studies were identified; 902 were excluded at title/abstract screen, 17 at full text screen and a further 7 during data extraction. 59 studies were included in the review.ResultsThirty-four studies reported the prevalence of fish/shellfish allergies in Europe. Prevalence rates based on self-reported allergy were presented in 22 studies, sensitisation rates were assessed in 8 studies using skin prick tests and 5 studies reported on serum IgE, sensitisation plus clinical history was obtained in 4 studies and 7 studies based prevalence data on food challenges. Depending on the assessment criteria prevalence ranged between 0% - 7%. Twenty-seven studies looked at the prevalence of fish/shellfish allergy across the rest of the world. Self-reported allergy was presented in 16 studies, 10 studies combined clinical history and clinician diagnosis, 7 studies measured sensitisation rates with a further 3 studies reporting a convincing clinical history plus sensitisation. Only 2 studies used food challenges to confirm suspected allergy. Depending on the assessment criteria prevalence ranged between 0% - 24.5%.ConclusionsVery few studies have established the prevalence of fish/shellfish allergy using the gold standard challenge criteria. Where this is used the worldwide prevalence rates of fish allergy ranges between 0%-1% and 0.2%-0.9% for shellfish allergy